Ultrasound-assisted biosynthesis of silver and gold nanoparticles using Clitoria ternatea flower

Abstract

This research focused on biosynthesis of silver and gold nanoparticles using Clitoria ternatea flower extracts under the ultrasound-assisted method. The synthesized nanoparticles were detected by UV-Vis spectrophotometric analysis, x-ray diffraction, scanning electron microscope, and transmission electron microscope. The effect of ultrasound method on physicochemical properties of the nanoparticles was compared to the use of reflux method. The influence of the character on biological activity of the nanoparticles were tested for their antibacterial activity against Klebsiella pneumoniae, Escherichia coli, Staphylococcus aureus, and Streptococcus pyogenes bacteria. Chemical activity of the nanoparticles was also evaluated as antioxidant by using radical inhibition by using 2,2-diphenyl-1-picrylhydrazyl radicals (DPPH) assay. The results showed that Clitoria ternatea flower exhibited reduction capability to form nanoparticles with the particle size ranging at 18-50 nm. In general, the ultrasound produces smaller particle size compared with reflux method for both silver and gold nanoparticles. The smaller particle size obtained from the ultrasound-assisted method compared to the Reflux method was found to give higher antibacterial activity toward tested bacteria. The nanoparticles demonstrated the antioxidative activity as shown by the DPPH inhibition at more than 50%. The results suggest that the use of Clitoria ternatea flower extracts as reducing agent and ultrasound-assisted synthesis are fit as a green method for the synthesis of silver and gold nanoparticles.